The present invention relates generally to aerosol cans, and more particularly to a device and method for use in placing overcaps on aerosol cans moving along a manufacturing line.
Like many products, aerosol cans are manufactured and assembled along continuous running assembly lines. When manufacturing aerosol cans, an overcap is installed on the top of each can to protect the spray components. Coordination of aerosol can and cap delivery along the assembly line can become complicated for even symmetrical can and cap configurations. Installation of the overcap onto the top of each can is often also quite complicated and difficult. Problems associated with overcap placement and installation are increased when overcaps are designed having tapered side walls, uneven top profiles, or other asymmetrical contours. It is difficult to apply uniform downward pressure on an asymmetrical overcap configuration using current manufacturing techniques.
One such technique that is known and utilized by the assignee of the present invention includes a rotating wheel having a circumferential surface with a plurality of depressions or recesses formed therein. The wheel is rotated on a horizontal axis and positioned above a plurality of vertically oriented aerosol cans traveling beneath the wheel. The recesses of the wheel each carry an overcap. The recesses and cans are coordinated so that one overcap is installed on each can. Pressure is applied by the rotating wheel to install the caps on the cans as the recess reaches the lower apex of the wheel above the can. When overcaps are designed having uneven, tapered or asymmetrical configurations, this pressure wheel technique requires that each overcap be properly oriented rotationally within its respective recess in order to evenly distribute pressure when installing the cap. Overcap orientation equipment and techniques are rather complicated and expensive to install and maintain.
U.S. Pat. Nos. 3,872,651 and 3,879,921 disclose overcap installation equipment for an aerosol can assembly line utilizing an overhead linear moving belt traveling above a conveyor belt carrying aerosol cans. The overhead belt is angled slightly downward to gradually move closer to the aerosol cans moving on the conveyor belt. A gradual downward force is applied by the overhead belt onto the overcaps resting on aerosol cans moving beneath the overhead belt. Fairly complex and numerous mechanical components are necessary to provide and operate the overhead belt that is used to seat the overcaps. Maintenance, installation, repair and overall component cost of such a construction are prohibitive.
There is a need for an improved overcap installation apparatus and method that can provide uniform downward pressure when installing overcaps, and particularly when installing asymmetrical, uneven or tapered wall configuration overcaps. Further, there is a need for an improved method and apparatus for installing overcaps that require no overcap rotational orientation regardless of the overcap configuration. There is also a need for a simpler, less expensive, more reliable, and more efficient overcap installation apparatus and method.
In accordance with the teachings of one example of the present invention, a capping device for installing overcaps onto a plurality of aerosol cans moving along a manufacturing line includes a pressure plate and a pressure wheel. The pressure plate has a cap contact surface on one side and a bearing surface on the opposite side. The contact surface is oriented to face overcaps resting on a plurality of aerosol cans moving past the pressure plate on the manufacturing line. The contact surface is rotatable about an axis so that an installation segment of the pressure wheel and contact surface moves in concert with the aerosol cans. The pressure wheel has a rotatable circumferential surface arranged to bear against part of the plate bearing surface to further bear the installation segment of the contact surface into contact with the overcaps of the plurality of aerosol cans.
In one example, the pressure wheel can be arranged to bear against a part of the plate bearing surface. In another example, the pressure plate can be a circular disc having a radially extending flange that defines a circular contact surface on one side and a circular bearing surface on its opposite side.
In a further example, a resilient support can be provided that supports and orients the pressure plate to an unbiased rotation plane generally perpendicular to the rotation axis. The resilient support permits the pressure plate to be reoriented to an offset rotation plane at an angle relative to the unbiased plane to bring the installation segment into abutment with the overcaps of the plurality of aerosol cans.
In yet another example, the pressure wheel can be constructed to hold the pressure plate in the offset rotation plane orientation as the plurality of aerosol cans move past the pressure wheel. In a still further example, an overcap infeed segment of the contact surface is spaced from the installation segment on the pressure plate and provides a cap infeed gap between the plurality of aerosol cans and the contact surface. The overcaps can be rested on each of the plurality of aerosol cans prior to reaching the installation segment.
In another example, the contact surface can be oriented at an angle relative to the rotation plane of the pressure plate so that the contact surface is generally perpendicular to the rotation axis when the pressure plate is in the offset rotation plane orientation. In a further example, the pressure plate can be a circular disc having a radially extending flange that defines a circular contact surface and wherein the flange is so angled relative to the rotation plane of the plate.
In another example, the pressure plate can be arranged to rotate about a generally vertical rotation axis. In still another example, the aerosol cans can be conveyed along a partial circular path beneath at least a portion of the contact surface of the pressure plate at a can velocity that essentially matches a rotation velocity of the pressure plate at a particular distance from the rotation axis.
In another example, a resilient support orients and supports a circular disc configuration pressure plate arranged to rotate about a vertical axis. The support has a plurality of vertically oriented pins extending from a rotary shaft hub, each pin having an upper pin shoulder that limits vertical travel of the disc and a spring that bears against a portion of the disc and biases the disc upward into contact with the shoulder. In a further example, the capping device can have a star wheel assembly arranged to rotate concentrically with the shaft hub and the rotary disc. The star wheel assembly can have a plurality of can receiving recesses in a circumferential surface adapted for guiding the aerosol cans along a path beneath at least part of the contact surface of the disc.
In one example according to the teachings of the present invention, a capping station is provided for installing an overcap on each of a plurality of aerosol cans moving along a manufacturing line. The capping station includes an aerosol can infeed conveyor that moves a plurality of aerosol cans to the station. An overcap infeed is adapted to initially rest an overcap on each of the aerosol cans that enter the station to produce a plurality of can pre-assemblies. The capping station also includes a pressure plate with a cap contact surface on one side and a bearing surface on the opposite side. The contact surface is oriented to face the overcaps of the can pre-assemblies moving past the pressure plate through the station. The contact surface is rotatable about an axis so that an installation segment of the contact surface moves in concert with the can pre-assemblies. The pressure wheel has a rotatable circumferential surface arranged to bear against a part of the pressure plate to further bear the installation segment against the overcaps of the can pre-assemblies. In various examples, the pressure plate and pressure wheel can have characteristics discussed above for the capping device.
In another example, a transfer wheel assembly can be arranged concentric and affixed for co-rotation with the pressure plate. The transfer wheel assembly can have at least one transfer star wheel with a plurality of can receiving recesses in a circumferential surface that are adapted for guiding the aerosol cans along the path.
In a further example, an infeed wheel assembly can be arranged to rotate about a second axis parallel to the rotation axis. The infeed wheel assembly can have at least one infeed star wheel with a plurality of can receiving recesses in a circumferential surface that are adapted for receiving aerosol cans from the infeed conveyor and delivering the aerosol cans to the transfer wheel assembly prior to reaching the installation segment of the pressure plate. In yet another example, a cap outlet of the overcap infeed is positioned between the infeed wheel assembly and the transfer wheel assembly.
In another example, a discharge wheel assembly can be arranged to rotate about a third axis parallel to the rotation axis, the discharge wheel assembly can have at least one discharge star wheel with a plurality of can receiving recesses in a circumferential surface that are adapted for receiving aerosol cans with installed overcaps from the transfer wheel assembly and delivering the aerosol cans to the discharge conveyor.
In one example according to the teachings of the present invention, a method of applying overcaps to aerosol cans moving along a manufacturing line is provided. The method includes providing a capping station on the manufacturing line. The capping station has a conveyor surface, a pressure plate and a pressure wheel. The pressure plate is rotatable about an axis and has a cap contact surface and a bearing surface and the pressure wheel having a rotatable circumferential surface. The circumferential surface of the pressure wheel is positioned to bear against a part of the pressure plate so that an installation segment of the contact surface is positioned nearer the conveyor surface. A plurality of the aerosol cans are delivered from an infeed conveyor to the capping station. An overcap is rested on each of the plurality of aerosol cans to form a plurality of can pre-assemblies. The can pre-assemblies are conveyed between the conveying surface and the installation segment of the plate contact surface while moving the can pre-assemblies through at least part of the capping station to install the overcaps on the can pre-assemblies. The aerosol cans with installed overcaps are then discharged from the capping station.
In another example, the method can include providing a circular disc pressure plate and arranging the disc to rotate about a generally vertical axis. In a further example, the method can include providing the pressure plate with a radially extending flange defining the contact surface. In a still further example, the method can also include rotating the pressure plate flange about the axis and moving the can pre-assemblies along a path at least a part of which is concentric with the pressure plate and beneath the contact surface. In yet another example, the method also can include rotating the flange and moving the can pre-assemblies at essentially the same speed over at least the part of the path beneath the contact surface.
In another example, the method can include resiliently supporting the pressure plate such that an unbiased rotation plane of the pressure plate is oriented generally perpendicular to the rotation axis. The pressure plate can be offset so that the rotation plane of the pressure plate is oriented at an angle relative to the unbiased rotation plane such that the installation segment is nearer the conveying surface. In a further example, the step of delivering can include conveying each aerosol can to an infeed segment of the pressure plate that is spaced from the installation segment. The step of resting can further include resting an overcap on each aerosol can disposed beneath the contact surface at the infeed segment. In still another example, the step of providing also can include providing a circular disc pressure plate having a radially extending flange defining the contact surface oriented at an angle relative to the rotation plane of the disc such that the contact surface is arranged perpendicular to the rotation axis when the disc is in the offset rotation plane orientation.
Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description.